Interactions between Shh pathway regulators and fetal alcohol exposure in mice

Shh 通路调节因子与小鼠胎儿酒精暴露之间的相互作用

• 批准号: 7938761
• 负责人: Robert S. Krauss
• 金额: $ 39.49万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7938761
• 关键词: 129/Sv Mouse; Alcohol consumption; Alobar Holoprosencephaly; Animal Model; Anterior nares; Apoptosis; Binding; C57BL/6 Mouse; Cell Surface Proteins; Clinical; Complex; Congenital Abnormality; Counseling; Defect; Development; Digit structure; Down-Regulation; Ectoderm; Embryo; Employee Strikes; Environmental Exposure; Environmental Risk Factor; Erinaceidae; Ethanol; Etiology; Face; Failure; Fetal Alcohol Exposure; Fetal Development; Frequencies; Genes; Genetic; Genetic Predisposition to Disease; Genetic Variation; Goals; Holoprosencephaly; Human; Impairment; Light; Limb Bud; Limb structure; Microforms; Modeling; Mus; Mutant Strains Mice; Mutation; Outcome; Pathway interactions; Pattern; Penetrance; Phenotype; Population; Pregnancy; Process; Prosencephalon; Protein Binding; Public Health; Reporting; Resistance; Role; Severities; Signal Pathway; Signal Transduction; Staging; Structure; Teratogens; Time; Ursidae Family; Zebrafish; alcohol exposure; craniofacial; developmental genetics; fetal; gene environment interaction; genetic analysis; genetic pedigree; in utero; insight; malformation; mouse model; mutant; mutation carrier; palatogenesis; public health relevance; receptor

DESCRIPTION (provided by applicant): Holoprosencephaly (HPE) is a common birth defect of the forebrain and midface with both environmental and genetic causes. Among the environmental factors is maternal alcohol consumption during early pregnancy. In addition, mutations in the Sonic hedgehog (Shh) signaling pathway have been identified in human HPE. The HPE phenotype of mutation carriers is highly variable, with the spectrum of effects ranging in a continuum from severe defects in the forebrain and midface to no clinical manifestation. The reason for this variability is un- known, but factors that may also be required include additional genetic influences or environmental exposures, during fetal development. Gene-environment interactions are likely to be involved in a complex malady like HPE; however, there are few models for this. Cdo and Boc are cell surface proteins that bind Shh and regulate pathway signaling strength in specific regions of the developing embryo. Cdo mutant mice display HPE with strain-specific severity: mutants on the 129/Sv background show very mild HPE with low frequency, while mutants on the C57BL/6 background show more severe forms at high frequency. Boc mutant mice are without overt effect, but 129/Sv Cdo;Boc double-mutants display severe craniofacial HPE features. We report that 129/Sv mice are resistant to ethanol-induced HPE; however, 80% of 129/Sv Cdo mutant embryos exposed in utero to ethanol display strong craniofacial HPE and bear a striking resemblance to Cdo;Boc double mutants. Furthermore, there is a strong reduction of Shh expression in the forebrain of ethanol-treated Cdo mutant embryos. Loss of Cdo and fetal ethanol exposure therefore synergize to produce HPE; this fact, plus that ethanol-treated Cdo mutant embryos are so similar to Cdo;Boc double-mutants, argues that loss of Cdo and ethanol exposure have a synergistic effect on Shh signaling. Limb and digit defects are also associated with human fetal alcohol exposure, and in utero ethanol exposure of C57BL/6 embryos results in malformations of the posterior aspects of limbs and digits. Shh is required for all posterior patterning of limbs and digits. Loss of Boc, but not Cdo, results in severe digit defects on a genetically-sensitized background. It is hypothesized that, similar to 129/Sv Cdo mutant mice and HPE, 129/Sv Boc mutant mice will be sensitized to ethanol-induced limb/digit anomalies. There is relatively little information available on how ethanol disrupts the known regulators of limb/digit patterning, and developmental genetic analyses of ethanol-treated C57BL/6 and 129/Sv mice will shed light on this process. The aims of this proposal are: 1) to analyze ethanol-induced HPE in 129/Sv Cdo mutant mice; 2) to identify mechanisms of ethanol-induced down-regulation of Shh expression in the forebrains of 129/Sv Cdo mutant mice; and 3) to analyze the role of the Shh pathway in ethanol-induced defects in limb/digit patterning. These studies involve analysis of a newly developed model of gene-environment interaction between a defined developmental mutation and ethanol in a common birth defect. Such information may have important public health impact and could ultimately aid in the counseling of mutation carriers. PUBLIC HEALTH RELEVANCE: Maternal alcohol consumption during early pregnancy can result in birth defects, and this may be influenced by genetic variation in the human population. This application focuses on a mouse model in which a combination of in utero alcohol exposure and a specific mutation leads to a devastating and common birth defect of the forebrain and midface, called holoprosencephaly. Studies on this model, and its extension to additional ethanol-associated birth defects, are proposed, with the goal of shedding light on how genetic susceptibility may influence the outcome of fetal alcohol exposure.

描述（由申请人提供）：前脑无裂畸形 (HPE) 是一种常见的前脑和中面部出生缺陷，有环境和遗传原因。环境因素之一是孕早期母亲饮酒。此外，在人类 HPE 中还发现了 Sonic Hedgehog (Shh) 信号通路的突变。突变携带者的 HPE 表型变化很大，其影响范围从前脑和中面部的严重缺陷到无临床表现。这种变异的原因尚不清楚，但可能还需要一些因素，包括胎儿发育过程中额外的遗传影响或环境暴露。基因与环境的相互作用可能与 HPE 这样的复杂疾病有关。然而，这方面的模型很少。 Cdo 和 Boc 是细胞表面蛋白，可结合 Shh 并调节发育胚胎特定区域的通路信号强度。 Cdo 突变小鼠表现出具有品系特异性严重程度的 HPE：129/Sv 背景上的突变体以低频率显示非常轻微的 HPE，而 C57BL/6 背景上的突变体以高频率显示更严重的形式。 Boc突变小鼠没有明显的影响，但129/Sv Cdo;Boc双突变体表现出严重的颅面HPE特征。我们报告 129/Sv 小鼠对乙醇诱导的 HPE 具有抵抗力；然而，在子宫内暴露于乙醇的 129/Sv Cdo 突变体胚胎中，80% 表现出强烈的颅面 HPE，并且与 Cdo;Boc 双突变体具有惊人的相似性。此外，乙醇处理的 Cdo 突变体胚胎的前脑中 Shh 表达显着降低。因此，Cdo 的损失和胎儿乙醇暴露会协同产生 HPE；这一事实，加上乙醇处理的 Cdo 突变体胚胎与 Cdo;Boc 双突变体非常相似，表明 Cdo 的损失和乙醇暴露对 Shh 信号传导具有协同作用。四肢和手指缺陷也与人类胎儿酒精暴露有关，C57BL/6 胚胎在子宫内接触乙醇会导致四肢和手指后部畸形。四肢和手指的所有后部模式都需要“嘘”。 Boc 而非 Cdo 的缺失会导致遗传敏感背景下的严重手指缺陷。据推测，与 129/Sv Cdo 突变小鼠和 HPE 类似，129/Sv Boc 突变小鼠将对乙醇引起的肢体/手指异常敏感。关于乙醇如何破坏已知的肢体/手指模式调节因子的信息相对较少，对乙醇处理的 C57BL/6 和 129/Sv 小鼠的发育遗传分析将揭示这一过程。该提案的目的是：1）分析129/Sv Cdo突变小鼠中乙醇诱导的HPE； 2) 鉴定乙醇诱导129/Sv Cdo突变小鼠前脑Shh表达下调的机制； 3) 分析Shh 通路在乙醇引起的肢体/手指模式缺陷中的作用。这些研究涉及对一种新开发的模型的分析，该模型是确定的发育突变与常见出生缺陷中的乙醇之间的基因-环境相互作用模型。此类信息可能会对公共卫生产生重要影响，并最终有助于突变携带者的咨询。 公共卫生相关性：怀孕早期母亲饮酒可能导致出生缺陷，这可能受到人群遗传变异的影响。该申请重点关注小鼠模型，在该模型中，子宫内酒精暴露和特定突变相结合，导致前脑和中面部出现破坏性且常见的出生缺陷，称为前脑无裂畸形。建议对该模型及其扩展到其他与乙醇相关的出生缺陷进行研究，目的是揭示遗传易感性如何影响胎儿酒精暴露的结果。